MBE and ALE of II-VI Compounds: Growth Processes and Lattice Strain in Heteroepitaxy

Abstract

Recently, dynamical behaviour of reflection high-energy electron diffraction (RHEED) patterns, i.e., RHEED intensity oscillations during molecular beam epitaxy (MBE) growth1,2 andj RHEED intensity variations during atomic layer epitaxy (ALE) growth3,4 of II–VI compounds have been reported. The period of the RHEED intensity oscillation exactly corresponds to a monolayer growth rate of the crystal by MBE. This technique has been utilized to calibrate beam flux, to control growth rate, and to measure quantum well thickness5. The temporal behaviour of specular beam intensity of RHEED during ALE3,4 reflects adsorption processes of impinging molecular beams. Adsorption time for monatomic layer is estimated from the temporal dependence of specular beam intensity. The specular beam intensity varies with time during suspension of ALE at high substrate temperature. This is due to sublimation processes of surface atoms. The sublimation time for the surface layer can be estimated3,4,6,7. Thus the investigation of dynamical behaviour of RHEED intensity gives important informations relevant to surface processes during MBE and ALE.